Sharing a personal history from a fairly anxious period this spring. Late 20s, high-stress work stretch, wanted to write down what a Selank experiment felt like from the inside rather than relying on how I'd remember it later. Not advice, just my account.
The thing I noticed most was a slight take-the-edge-off quality in the first hour or two, a sort of lowered reactivity when my inbox lit up. It was subtle, never sedating. Sleep is where I'm least sure: my sleep tracker didn't show anything I'd call a real shift in the numbers, even though a couple of nights subjectively felt easier to fall into. Placebo-prone territory, and I know it.
Cognitively I didn't get the "clarity" some people describe. Same distractible me. After about six weeks the edge-off feeling seemed to fade, whether from tolerance or from my work simply calming down, I can't tell you. The human research here is small, so I'm treating my own read as a diary entry, not a finding.